49 research outputs found
Prospects for Constraining Cosmology with the Extragalactic Cosmic Microwave Background Temperature
Observers have demonstrated that it is now feasible to measure the cosmic
microwave background (CMB) temperature at high redshifts. We explore the
possible constraints on cosmology which might ultimately be derived from such
measurements. Besides providing a consistency check on standard and alternative
cosmologies, possibilities include: constraints on the inhomogeneity and
anisotropy of the universe at intermediate redshift ; an
independent probe of peculiar motions with respect to the Hubble flow; and
constraining the epoch of reionization. We argue that the best possibility is
as a probe of peculiar motions. We show, however, that the current measurement
uncertainty (K) in the local present absolute CMB
temperature imposes intrinsic limits on the use of such CMB temperature
measurements as a cosmological probe. At best, anisotropies at intermediate
redshift could only be constrained at a level of and peculiar
motions could only be determined to an uncertainty of km
s. If the high CMB temperature can only be measured with a precision
comparable to the uncertainty of the local interstellar CMB temperature, then
peculiar motions could be determined to an uncertainty of .Comment: 8 pages 2 Figures, PRD Submitte
Experimental charge-density study on the nickel(II) coordination complex Ni(H3L) NO3 PF6 H3L = N,N ',N ''-tris(2-hydroxy-3-methylbutyl)-1,4,7-triaza-cyclononane : a reappraisal
The effect of the mode of administration and the dose of a carcinogenic agent on the development of morphological changes in the focus of tumor formation
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Microbiological, Geochemical and Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado
Galaxy and Mass Assembly (GAMA): small-scale anisotropic galaxy clustering and the pairwise velocity dispersion of galaxies
The galaxy pairwise velocity dispersion (PVD) can provide important tests of non-standard gravity and galaxy formation models. We describe measurements of the PVD of galaxies in the Galaxy and Mass Assembly (GAMA) survey as a function of projected separation and galaxy luminosity. Due to the faint magnitude limit (r < 19.8) and highly complete spectroscopic sampling of the GAMA survey, we are able to reliably measure the PVD to smaller scales (r⊥ = 0.01 h − 1 Mpc) than previous work. The measured PVD at projected separations r⊥ ≲ 1 h − 1 Mpc increases near monotonically with increasing luminosity from σ12 ≈ 200 km s − 1 at Mr = −17 mag to σ12 ≈ 600 km s − 1 at Mr ≈ −22 mag. Analysis of the Gonzalez-Perez et al. (2014) GALFORM semi-analytic model yields no such trend of PVD with luminosity: the model overpredicts the PVD for faint galaxies. This is most likely a result of the model placing too many low-luminosity galaxies in massive haloes